Method for cutting disks or blanks from untrimmed commercial sheets



ma m w22.. 1,439,393

F. A. ASSMANN. JR. METHOD FOR CUTTING D1 sKs 0R BLANKS FROM UNTRMMED COMMERCIAL SHEETS. FuLED oec. 23. l9l9,

Patented Dec. 19, 1922.

UNITED STATES PATENT oFFlcE.

FRANK A. ASSMANN, JR., 0F CHICAGO, ILLINOIS, ASSIGNOR TO CONTINENTAL CAN COMPANY, INC., 0F SYRACU'SE, NEW YORK, A CORPORATION 0F NEW y,.YOIRK.

METHOD FOR CUTTING DISKS OR BLANKS FROM UNTRIMMED COMMERCIAL SHEETS.

Application filed December 23, 1919. Serial No. 346,942.

10 all wle-0721.271? muy concern y Beit known that I, FRANK A. Ass-MANN, Jr., a citizen of the United States, residing at Chicago, in the county of (look. State of Illinois, have invented certain new and useful Improvements in Methods of Cutting Disks or Blanks from llntrimmed Commercial Sheets, of which the following is a description, reference being had to the accompanying drawing and to the figures of reference marked thereon.

The invention relates to new and useful improvement-s in a method of cutting disks orblanks from a commercial sheet, and more particularly to a method of cutting round can ends from a sheet of metal.

It is welll understood that commercial sheets of tin of a given size vary slightly in length, and'it has been long the practice to trim the sheet to a predetermined length or provide gaging surfaces by a preliminary cutting of the sheet so that the sheet of metal may be presented to the dies for cutting out the can ends, a maximum number of can ends .cut from the sheet, and without any die overlapping the edge of the sheet during its operation. An object of the invention "is to provide a method which may be used for cutting a maximum number of can ends from. a. commercial sheet of tin of a given size without the preliminary end trimming of the sheet or the forming of gaging surfaces.

A further object of the invention is to provide a method of the above character of cutting untrimmed connncrcial sheets of tin 'wherein blanks may be cut from the waste ends ofthe sheet during the presentation ofthe sheet to the dies for cutting the can ends.

In the drawings, which show byway of illustration one arrangement of t-he dies and the sheets for carrying out the above method v Figure l is a plan view sho-Wing, more or less diagrammatica-lly. a. series of dies and a feeding mechanism for presenting sheets, one after the other, .to the dies for the cutting of the same;

Fig. 2 shows a sheet having been cut throughout by the improved method; and

Fig. 3 shows more or less diagrammatically one way of rendering the die idle in carrying out the new method.

While "the invention in its broadest aspects is directed to a method of cutting disks or blanks of any desired shape or size from sheets of material of any character, it is more particularly directed to a method of cutting can ends from untrimmed commercial sheets of a given size and, therefore, detailed description will be given as to one way of carrying out the method of cutting can ends, it being understood that so far as the principle of the invention is concerned and. the scope of the claims, other blanks than can ends may be cut from the sheet and the sheets operated upon may be of any desiredmaterial.

It is .wel-l known that the commercial sheet of tin of a given size varies as to length and that the edges are often slightly curved in one direction or the other, due to the finishing of the sheet in the mills. Prior to the present invention, it has been customary to trim the sheet to a predetermined length and straighten the edges prior to the presenting of the same to a punching machine for cuttingout the ends. Another method of preparing the sheet as it comes from the mill for punching has been to cut notches inthe edges of the sheet to form gaging surfaces which may be used for positioning the sheet relative to -a gang of dies operating by the reversing or shifting of the lsheet to cut all of the ends therefrom. I

The present method is directed particularlyto the cutting of the can ends from an untrimmed commercial sheet which is fed step Iby step to a gang of dies, and the invention consists particularly in feeding the sheet at each stepthe distance between the centers of two can ends which are to be cut, cutting the sheet lby independently controlled dies operating simultaneously to cut certain of the can ends. and so; controlling each die that it will be idley when any portion of the sheet is beneath the same eX- cept a portion of sufficient size to cut a full can end. It is well known that if a die overlaps the edgeof the vsheet so as to thed purpose which will rocation and the next reciprocation pass wholly through the sheet so that there is no overlapping of the edge of the metal of the sheet during any reciprocation of the die. lVlien, however, the sheet is not trimmed to a predetermined length, it will be readily seen that the sheet would project across the path of the die in the reciprocation of the die as the front edge of the sheet approaches the die. My method contemplates so controlling the die as to render it idle during this particular stroke, and thus avoid the die operating to cut a partial disk or segment from the sheet.

Referring to the draWings,-the sheet from which the can ends are to be cut is indicated at S. The sheet is the ordinary com mercial sheet which is cut at the. tin mill during the process of manufacture, so as to produce so-called standard sheets of a given size. These sheets, however, as above noted, vary slightly in length. The sheets without being trimmed are placed on a suitable support and are fed' to a gang of dies by a feed chain or the like, indicated at l in the drawings. Said feed chain is operated intermittently and is rprovided with suitable lugs 2 which engage the end of the sheet and feed the sheet step by step through the machine. In' one embodiment of the method, a series of dies, indicated at 3, 4, 5, 6 and 7 are used, and these dies are set in a diagonal line relative to the direction of feed, which is indicated by the arrow r in the drawings. Each of these dies is operated from a main shaft, such, for example, as is indicated at 8 in Fig. 3 of the drawings. This shaft carries a rotating cam 9 having a series of cam projections 10. A reciprocating die, indicated at 11 is held in ralsed position by a spring 12 andis forced downwardly by the cam projections 10 to cause the die to cooperate with a lower fixed die 13 in the bed ofthe machine for cutting and forming the can ends. Thesel cooperating dies may be of anyfsuitable construction, and the present illustration 'is diagrammatic and solely for the purpose of illustrating` the principles of the invention.

It is noted that the cam projections 10 are equally spaced and are seven in number, as shown. in Fig. 3. There is also a blank space 14 where there is no cam projection. It will be understood that there is a cam disk associated with each cutting die,land

the projections of the dies 4and 6' lare'gsix 1n number with two idle spaces for be hereinafter described.

1 The-sheet, as above stated, is a commercial srheet andthe length of the sheet fromv to rv, while approximately the sizenecessary to cut the can ends therefrom may be slightly greater but must never be less than the prescribed length from which the can ends can be cut. The sheet of metal is shown in dotted lines as presented to the first die 3. The length of the sheet wis such that the extreme forward edge of the sheet underlies the die 3, but at this time the cam disk is so timed that the blank space is directly over 4the die plunger and, therefore, the die will not be depressed 'during the interval of rest of the sheet at this position. The sheet is then fed one step forward, which brings the sheet underneath the die 3 and the can end, indicated at b in Fig. 2 of the drawings, will be cut.

The sheet is then fed another step forward and the can end, indicated at c, is cut. At this position of the sheet, the die 4 overlaps the edge of the sheet, but the cam disk for operating the die 4 is so timed that there is a blank space above the die plunger and, therefore, the die 4 will be idle and no cutting of the sheet will be performed by this die.

At the next stepy in the forward movement of the sheet, the can ends indicated at cZ-(Z are cut, the dies 3 and 4 now being active to cut can ends from the. sheet. At this time, the die 5 slightly overlaps the edge of the sheet, and the operating cam disk therefor is so timed that there is a blank space above the die plunger and the die will be idle. `The same is true of the dies 6 and 7 they are caused to reciprocate simultaneously1 with the other dies ex- 100 cept when a die overlaps the edge of the sheet and then the die plunger is idle. After having cut the can ends e-e-e, the can ends f-f-f are cut, and then the can ends gg-gg are cut, and then t-L-L-t-L 105 are cut, and so on until the can ends indicated at z', y', lo, Z, m and n are cut. At the cutting of the can end n the entire sheet is cut and may be discharged from the Inachine.

In Fig. 1 of the drawings there is shown a second sheet S following after the first sheet S, and the method is also illustrated of cutting out the waste ends of the sheet. There are -sections between the can ends 115 b, d and e from which a blank indicated at a may be cut, and also a similar space between the can ends e, g and 71. from which another blank a is cut. There are also spaces at the other ends of the sheet fromv which blanks a-a may be cut.

In order to accomplish this, four dies, in-l dlcated at .l5-15 and 1-6'16.are provided, Y which dies may all be carried by a single head operated by a cam disk having a'sing'le 125 cam projection withy seven idlespaces. This' cam disk will be so timed that, when the two sheets are in the position indicated in Figs. 2 to 4, the dies 15--15 and 16-16 will be operated to cut out the blanks a-a and l a--a. The blanks ai-a are cut from the forward sheet, while the blanks (z-a are cut from the sheet following. After this operation, these dies remain idle until the end of the sheet following reaches the posi.- tion of the forward sheet, and they will then be operated to cut again the blanks a--a and a-a. The dies 4 and 6 are operated by cam disks having two idle spaces, for the reason that only Six can ends are cut by these dies, while seven can ends are cut by the other dies. Therefore, when the die et overlaps the rear edge of a sheet, it-

must be idle and at the next step it will overlap the front edge of the following sheet and it must be idle.

From the above, it will be apparent that the method of cutting can ends from an untrimmed commercial sheet of tin consists in feeding the sheet step by step the distance between two can endA centers, cutting the can ends by reciprocating dies which are so controlled that thedies are idle when the edge of a sheet is underneath a die. These can ends are cut as close together as can be cut without breaking through the metal between openings formed by the cutting ofthe sheet and if the sheet is to be cut to advantage, the entire length of the sheet should be as near as possible seven times the size of the can end plus the width of the thread of metal between the openings and between the openings and the end of the sheet. Vhen the sheets are trimmed prior to punching, they will be cut to a predetermined length, depending upon the size of `the openings formed or the can ends cut from the sheet. lf it is trimmed before the sheet is presented to the dies, then a die may be passed close to the end of the sheet for cutting the same at one reciprocation, and then wholly within the sheet 'at the next reciprocation -and leave a very small thread of metal between the openings and between the openings and the end of the sheet. However, if the sheets are untrimmed and are cut as they come from the mills, thenthis accuracy of the length is not present even withstandard sheets of a given size and the reciprocating die whichv should pass the edge of the sheet may slightly overlap the same. .By my method, however, thedie is rendered idle when a portion of the sheet is beneath the same except a portion of sufficient size to cut a full can end. In the drawings the dies are show-n asarranged in a diagonal line and come into operation one after the other, and it will be readilyunderstood that they may be arranged in other ways and from certain aspects of the invention a single die may be used for cutting blanks from a `narrow strip of metal, the same principle being employed of rendering the die idle as the advance edge of the sheet comes underneath the die and then beginning the cutting operations at the next step forward of the sheet when the die will; be wholly over the sheet. It-fwill be readily understood 'that the feeding mechanism may be of any desired character and a rectifier may be used in connection with a chain conveyor in order to bring about an accurate feed of the sheet at each forward step thereof.

As above noted,4 while the invention has been described for cutting can ends from commercial sheets of tin, it will be understood that it may be equally well used in cutting blanks of any kind and from any character of material, the essential feature being thatk the die or dies should be so cont-rolled as to be idle when the die overlaps the edge of the sheet and would be liable to cut an incomplete blank which would be hard on the die and so render it ineflicient.

Having thus described the invention, what is claimed as new is 1. The method of cutting blanks from untrimmed commercial sheets ofa given size, comprising feeding the sheets step by step to a plurality of reciprocating dies of a given size to correspond with the size of the sheet worked upon and controlling the movements of said dies so that whenany die overlies either the advanced or rear edge of the f sheet the die is rendered idle.

2. The method of cutting can ends from untrimmed commercial sheets of tinof'a given size comprising feeding the sheets step by step to a series of dies of a given size to correspond to the size of the sheet worked upon and loperating simultaneously to cut certain of the ends, and providing controlling means whereby any die which overlies the advanced'or rear edge of the sheet will be rendered idle.

3. rlhe method of cutting can ends from untrimmed commercial sheets of tin of a given size comprising feeding the sheets step by step to a series of dies of a given size to correspond to the siz'e. of thesheet worked upon and operating simultaneously to cut certain ofthe ends, and providing controlling means whereby any die which overlies the advanced or rear edge of the sheet will be rendered idle, simultaneously cutting blanks from the waste sections at the ends of the sheets and causing said dies cutting said blanks to remain idle while in any other position relative to the sheet than that for cutting the waste sections. l

In testimony whereof, l affix my signature. 

